Braking mechanism for elevator-cars.



Patented Jam 2l, I902.

.0. m. FRITSCH. BRAKING MECHANISM FOR ELE YATOB'CARS.

(Application filed July-8, 1901.)

(N0 Model.)

THE NORRIS Parzns coy. Puorolrma, WASHINGTON, n. 5.

NlTED- STATES PATENT OFFICE.

OSCAR M. FRITSOH, OF PHILADELPHIA, PENNSYLVANIA.

BRAKING MECHANISM FOR ELEVATOR-CABS.

SPECIFICATION forming part of Letters Patent No. 691 ,617, dated January 21, 1902. Application filed July 8, 1901. Serial No. 67,515. No model-l To all whom it may concern:

Be it known that I, OSCAR M. FRITSCH, a citizen of the United States, and a resident of Philadelphia, Pennsylvania, have invented certain Improvements in Braking Mechanism for Elevator-Oars, of which the following is a specification.

One object of my invention is to provide a quick and firm holding friction clutch or brake for elevator-cars, a furtherobject being to efiect the ready release of the brake and a controlled descent of the car after the brake has beenapplied by reason of accident,

and a still further object being to provide for the ready rewinding of the controlling-rope on the drum in restoring the parts to operative position.

In the accompanying drawings, Figure 1 is a side view, partly in plan or top view and partly in sectional plan, of sufficient of an elevator-car audits guides to illustrate my invention. Fig. 2 is a View of the same partly in vertical section and partly in elevation. Fig. 3 is a transverse section on the line a :0, the elements of the mechanism, and Fig. 5 is a view illustrating another construction embodying the invention.

Part of the floorof an elevator-car is shown at 1 and certain of the transverse floor-beams at 2, and to the latter are secured two beams 3 3, which extend across the car from side to side or from corner to corner, depending upon the location of the vertical guides 4 in the elevator-well.

Secured to the beams 3 3 and bridging the same are bearings 5, in which are free to turn the heads of a drum 14, internally threaded to receive a pair of threaded bolts 6, one right handed and 'the other left handed, which operate the wedges 7, whereby the brake-shoes are forced into contact with the projecting. webs of the guide-bars 4. Each of the wedges is duplex -that is tov say, it is constructed to act upon a pair of brake-bars 8, guided upon transverse bolts 8 and carrying the brake shoes 9, which when the wedges are drawn in the direction of the arrows, Fig. 1, are forced firmly into contact with the webs of the guide-bars 4, so as to stop the descent of the car. Springs 8 con- Fig. 4is a detached viewof one of 'stantly maintain each of the brake-bars 8 in contact with its respective wedge member 7. The outer face of each of the brake-bars S has in the present instance rounded or beveled lugs 10 for entering corresponding recesses in the engaging face of the wedge, so that the engaging faces of these recesses and lugs will be more abrupt than the inclined meeting faces of the wedge and brake-bar, the recesses being of such extent that when the wedges are first drawn inward toward the center of the car there will bea quick action of the brake-bars tending to bring their shoes into contact with the projecting webs of the guide-bars 4, this quick preliminary action being followed by a slower more powerful action, due to the lesser angle of the inclined inner sides ofthe wedges. Hence the brakeshoes will be brought into contact with the bar's4 the instant the safety device begins to act, thus preventing any considerable drop of the car before bringingthe brakes into op eration, while at thesame time the powerful action of the brakes, due to the slight angle or bevel of the inner faces of the wedges, is insured.

Each of the wedges 7 has a head 12 swivteled'to the outerend of its corresponding out imparting any turningmovement to the wedge structure. The threaded portions of the bolts 6 are adaptedto threaded openings formed in the ends of the drum 14, which receives the usual controller-rope 15, with which braking devices of this character are provided, this controllerrope being normally free to move with the car, but being under control of a speed-'governor'adapted in case of any sudden increase in the speed of movement of the car to grip and hold the controller-rope, so that the continued movement of the car will effect the turning of the drum 14.

Splined upon each of the screw-bolts 6 is a worm-wheel 16, which has a hub free to turn in a transverse bearing on the frame, but longitudinally confined thereto, and each of these worm-wheels mesheswith a worm 17 on a transverse shaft 18, adapted to hearings on the fixed frame and having at its outer end a bevel-pinion 19, these two pinions meshing with bevel-wheels 20 on a longitudinal screw-bolt 6, so thatthe latter can turn with-- IOO shaft 21 and one of said bevel-wheels 20 meshing with a pinion 22 on a short vertical shaft 23, which is squared or otherwise formed at its upper end, so that it can be turned by means of a suitable wrench inserted through a trap-door in the floor of the elevator-car.

On one end of the drum l4 isaspur-wheel 25, which meshes with a spur-pinion 26 on a short shaft adapted to a suitable bearing on the fixed frame and carrying a bevel-pinion 28, which meshes with a bevelwheel 29 on a short vertical shaft 30, likewise squared or otherwise formed at the upper end for the reception of a wrench inserted through a trapdoor in the floor of the elevator-car.

In the operation of the device the pull upon the controller-rope 15 turns the drum 14, so i that the ends of the hubs of the same act as nuts upon the screw-bolts b and draw the. same inwardly or toward the center of the means of the worm-wheels lo and the gearing connected therewith,the turning of said worm- 1 wheels in the proper direction causing turning of the screw-bolts 6, so as to back out the same from the nuts formed by the ends of the drum l4: sufficiently to release the hold of the brake-shoes upon the guide-bars 4:; but as soon as this has been done the slight descent of the car again imparts pull to the governing-rope and causes operation of the drum 14, so as to again apply the brakes, the Wormwheels 16 being then again operated so as to efiect a further backing off of the screw-bolts and wedges and a further limited descent of the car, and these operations being repeated until the car reaches the landing.

Instead of forming the lugs 10 upon the brake-bars and the recesses in the wedges a reverse construction may be adopted, and it is obvious that the brake-bars and wedges may be so disposed that the application of the brakes will be effected by the outward movement of the wedges instead of by inward movement of the same.

Myinvention is also applicable to that class ofbrakingdevicesin which thebrake-shoesare carried by leverssuch, for instance, as those shown at 31 in Fig. 5, the wedges in this case having enlarged heads with rounded or beveled ends 31, adapted to recesses in the levers, said beveled ends and recesses presenting more abrupt engaging surfaces than the beveled inner sides of the levers themselves, so as to provide for the desired graduated movement of the brake-levers.

One of the important advantages of my improved elevator safety device arises from the large clearance between the brake-shoes and the guide-bars under ordinary circumstances. In safety devices as heretofore constructed the shoes were necessarily very close to the guide-bars at all times, and the slight vibration of the elevator-car under running conditions causes a greater or less wear of the said shoes. It was therefore a difficult matter to keep the shoes in condition for use, and it frequently happened that when most needed they failed to grip the guide-bars, owing to their worn condition. My device prevents any possible wear of the brake-shoes 1 except when in actual use to prevent an accident, they being held at all other times far enough from the guide-bars to avoid contact therewith. The drum 14: preferably has a limited amount of play between its bearings, so as to compensate for anyinequality in the brake-bars l or shoes 9 and insure the pressure of the shoes upon each of the brake-bars with an equal amount of pressure when the brake is applied.

In order to insure the coiling of the safety rope or cable 15 snugly upon the drum 14, said rope in its passage to the drum from the guide-roller 32 passes between guide-lugs on a block 33, which is mounted so as to be free to slide upon a bar 34, the latter being mounted in fixed bearings on the elevator and having a projecting notched lug 35, which ongages with one of the flanges of the windingdrum and serves to maintain the bar always in the same lateral position in respect thereto. The sliding block 33 is acted upon by one or more springs 36, so that it has a constant tendency to press the rope as it is being wound upon the drum toward the coils previously wound thereon,thus insuring close winding of the rope and rendering available the maximum capacity of the drum, asshown in Figs. 1, 3, and 4.

Having thus described my invention, I claim and desire to secure by Letters Patent-- l. The combination in braking mechanism for elevator-cars, of the brake-operating wedges, screw-bolts connected thereto, a controller-drum having nuts engaging said screwbolts, and means whereby the bolts can be turned independently of the drum, substantially as specified.

.3. The combination in braking mechanism for elevator-cars, of the brake-operating drum of an elevator-car, with a bar engaging one of the flanges of said drum, and a sliding brake-rope guide mounted on said bar, and a I 5 spring acting on said guide to move it toward that flange of the drum which is engaged by the bar, substantially as specified.

In testimony whereof I have signed my name to this specification in the presence of 20 two subscribing witnesses.

OSCAR M. FRITSOH.

Witnesses:

F. E. BEoHT'oLD, WILL. A. BARR. 

